General Session: Value and Outcomes in Spine Surgery - Hall F

Presented by: S. Horn

Author(s):

S. Horn(1), P. Passias(1), R. Lafage(2), J. Smith(3), G. Poorman(1), B. Diebo(4), C. Bortz(1), F. Segreto(1), R. Hart(5), D. Burton(6), C. Shaffrey(7), D. Sciubba(8), E. Klineberg(9), T. Protopsaltis(1), F. Schwab(2), S. Bess((1)0), V. Lafage(2), C. Ames((1)(1)), International Spine Study Group

(1) New York University Langone Orthopedic Hospital, Division of Spinal Surgery, New York, NY, United States
(2) Hospital for Special Surgery, Department of Orthopaedic Surgery, New York, NY, United States
(3) University of Virginia, Department of Neurosurgery, Charlottesville, VA, United States
(4) SUNY Downstate Medical Center, Department of Orthopaedic Surgery, Brooklyn, NY, United States
(5) Swedish Neuroscience Institute, Department of Orthopaedic Surgery, Seattle, WA, United States
(6) University of Kansas Medical Center, Department of Orthopaedic Surgery, Kansas City, KS, United States
(7) University of Virginia, Department of Orthopaedic Surgery, Charlottesville, VA, United States
(8) Johns Hopkins University, Department of Neurosurgery, Baltimore, MD, United States
(9) University of California Davis, Department of Orthopaedic Surgery, Sacramento, CA, United States
(10) Denver International Spine Center, Department of Orthopaedic Surgery, Denver, CO, United States
(11) University of California San Francisco, Department of Neurosurgery, San Francisco, CA, United States

Abstract

Introduction: Prospective cervical deformity (PCD) patients (pts) have recently been assessed with ACD and adult spinal deformity (ASD) classifications with short follow-up. This study describes PCD pts with cervical (Ames) deformity scheme at baseline and 1-year post-operative and correlates modifier grades with outcomes. This study aims to utilize the Ames cervical classification to assess 1 year ACD outcomes.

Methods: Retrospective review of prospectively collected cervical deformity database. PCD pts ≥18yrs with pre-/post-op (1Y) radiographs. Pts were classified with Ames (A-ACD) scheme. A-ACD primary deformity descriptors (C=cervical; CT=cervicothoracic junction; T=thoracic; S=coronal) and alignment modifiers (cSVA, TS-CL, mJOA, Horiz) were assigned. Baseline univariate description evaluated demographics, clinical intervention, and Ames deformity driver types. Patients were evaluated for improvement and meeting MCID for mJOA, NDI, and EQ5D.

Results: The 73 ACD patients were categorized as: C=41 (56.2%), CT=18 (24.7%), T=9 (12.3%), S=5 (6.8%). By Ames modifier improvement at 1Y, 13 (17.8%) improved in mJOA score, 26 (35.6%) in cSVA grade, 19 (26.0%) in Horiz, and 15 (20.5%) in TS-CL (Figure 1). The distribution of patients without severe modifier grades at 1Y across all Ames descriptors were as follows: 100% cSVA, 27.4% TS-CL, 67.1% Horiz, 69.9% mJOA. At 1Y the highest mJOA modifier grade differed across types (C=26.3%, CT=15.4%, T=0.0%, S=0.0%, p=0.003). Higher PT was observed in patients with high (1+2) cSVA grades (58.3% vs. 28.0%, p=0.013) and high (2+3) mJOA (64.0% vs. 39.6%, p=0.041) scores at baseline. 1Y post-operatively, only S deformities differed in cSVA grade distribution (0=20.0%, 1=80.0%, 2=0.0%, p=0.048) and severe myelopathy (mJOA=3) prevalence differed between Ames-ACD deformity descriptors (C=26.3%, CT=15.4%, T=0.0%, S=0.0%, p=0.033). Improvement in the mJOA modifier correlated with reaching 1Y NDI MCID in the overall cohort (r=0.354, p=0.002). For type C, cSVA improvement correlated with reaching NDI MCID at 1Y (r=0.387, p=0.016). The number of Ames modifiers a patient improved in from baseline to 1Y correlated to reaching 1Y mJOA MCID (r=0.344, p=0.003). The number of Ames modifier improvements also correlated with reaching an increasing number of MCIDs for mJOA, NDI, and EQ-5D (r=0.272, p=0.020).

Conclusions: Ames-ACD classification can effectively describe cervical deformity patients' alignment and outcomes at 1-year. Improvement in radiographic Ames modifier grades have a significant correlation to 1-year outcomes and alignment correction.